Numerous situations exist in which a body cavity needs to be catheterized to achieve a desired medical goal. One relatively common situation is to provide nutritional solutions or medicines directly into the stomach or intestines. A stoma is formed in the stomach or intestinal wall and a tube is placed through the stoma. This surgical opening and/or the procedure to create the opening is common referred to as “gastrostomy”. Feeding solutions can be injected through the tube (i.e., a feeding tube) to provide nutrients directly to the stomach or intestines in a procedure generally known as enteral feeding. A variety of different feeding tubes intended for enteral feeding have been developed over the years. These devices are frequently referred to as “gastrostomy tubes”, “percutaneous gastrostomy catheters”, “PEG tubes”, “enteral feeding tubes” or “enteral feeding catheters.”
To prevent the PEG tube from being pulled out of the stomach/intestinal wall, various types of retainers are used at a distal end of the catheter. Examples of conventional devices with Malecot tips or similar expanding tips are found in, for example, U.S. Pat. No. 3,915,171 for “Gastrostomy Tube” issued to Shermeta; U.S. Pat. No. 4,315,513 for “Gastrostomy and Other Percutaneous Transport Tubes” issued to Nawash et al.; U.S. Pat. No. 4,944,732 for “Gastrostomy Port” issued to Russo; and U.S. Pat. No. 5,484,420 for “Retention Bolsters for Percutaneous Catheters” issued to Russo. Exemplary commercial products include the Passport® Low Profile Gastrostomy Device available from Cook Medical, Inc. of Bloomington, Ind. and the Mini One™ Non-Balloon Button available from Applied Medical Technology, Inc. of Brecksville, Ohio.
Feeding tubes that are initially placed during the gastrostomy procedure have non-inflatable bumpers, bolsters, Malecot tips or similar expanding tips made of a resilient material. These devices are passed through esophagus of a patient and into the stomach or intestinal space. The narrow tube end of the device is pulled through the stoma and the bolster or bumper which is much larger than the stoma is retained in the stomach or intestinal space to prevent the device from falling out. It is generally thought that the non-inflatable bumper or bolster helps the stoma site heal properly and form a desired shape.
If the feeding tube having the non-inflatable retainer needs to be replaced, it is frequently replaced with a feeding tube that employs an inflatable balloon as the retainer. The balloon, typically made of a “soft” or elastomeric medical grade silicone, is attached to the end of the catheter and is deflated for insertion through the stoma and then inflated to hold the enteral feeding assembly in position.
If the enteral tube is to be left in the stoma for some period of time, it is not uncommon for the tissue immediately surrounding the stoma, itself, to become sensitive to the presence of the components of the device including the base and the catheter or feeding tube. It is known that trapping moisture and not allowing the stoma site to experience air circulation can cause issues such as irritation, granulation tissue formation, infection and other problems. Standard length G-tubes use a slideable retention ring that is placed against the patient's body and most rings have raised pads to distribute the force and openings to allow air passage. See for example U.S. Pat. No. 4,666,433 to Parks. Low-profile devices, also called MIC-KEY devices, rest against the body but most designs do not allow adequate air circulation and/or force distribution. See for example U.S. Pat. No. 5,997,503 to Willis et al. and U.S. Pat. No. 20011/0152762 to Hershey et al. One attempt that has been tried is to raise the head from the body with legs/spacers extending from the body. See for example U.S. Pat. No. 4,798,592 to Parks. WO 01/603313 to Meier et al. discloses a low profile gastrostomy tube with an external retention member having a body with an axial opening and opposed legs which are adapted to abut the outer abdominal wall of a patient. WO 00/50110 to Meier et al. discloses a securing device for a low profile gastrostomy tube. The external retention member includes an annular body and two generally opposing grooves which are formed between respective legs and the annular body. Accordingly there is a need for an enteral feeding device that minimizes contact with the area of tissue immediately surrounding the stoma, especially on the external surface of the stoma.
Another problem with prior enteral feeding tubes is the manner in which the tube is connected or formed at its juncture with the underside of the base or head of the device. Some designs used what are termed bolsters, transition necks or strain relief necks which are areas of added material used to reinforce the juncture between the proximal end of the tube and the underside of the base. The use of this added material, especially when the tubes are formed from silicone rubber, tends to reduce the formation of stress risers in the tube material which can result in leaks in either or both of the inflation lumen and the feeding lumen located in the tube. Leaks in the tube are often the result of the rocking motion the base and tube experience during use as a result of the handling of the device during the administration of food and/or other liquids and drugs as well as the rocking action the device experiences due to the normal movements of the patient. The problem is that the use of this reinforcing material thickens the portion of the device which is in the immediate vicinity of the stoma thereby increasing the contact of the device with the stoma tissue thereby retarding the healing process and reducing the ability of fresh air to circulate around the stoma and promote tissue wellness.
Referring first to FIGS. 1 and 2 of the drawings there is shown a prior art enteral feeding tube assembly 10 including a base 12, a tube 14 and an inflatable balloon 16. As shown in FIG. 2, the assembly 10 extends through a stoma 18 formed in a portion of an animal or human such as the skin or stomach wall 20. The underside 22 of the base 12 rests on and partially in the stoma 18 and the tube 14 extends into the intended portion of the body cavity and is held in place by the inflatable balloon 16. The tube 14 itself typically has one or more fluid channels or lumen. One lumen 24 is used to pass fluids and semi-solid materials such as food, liquids and medications while a second lumen 26 is commonly supplied to allow inflation of the balloon 16. Due to the fact that the person or animal in which the assembly 10 is placed is prone to moving and due to the fact that the assembly is subject to further movement and rocking action when the caregiver is utilizing the assembly 10 to administer food, medications and other liquids, gases and semi-solid materials, the assembly 10 is subject to stresses which can, with time, weaken the assembly 10 and possibly cause what are called “stress risers” in the assembly material which are cracks and holes which can lead to leaking thereby causing the balloon 16 to deflate or the other delivered materials to leak into a non-intended area of the body cavity. In an attempt to minimize this problem, the underside 22 of the base 12 is often configured with bolstering material 28 in the form of what is called a transition neck or strain relief neck to given added integrity to the structure of the assembly. This has been found to be particularly necessary when materials such as silicone are used to form the base 12 and/or the tube 14. This added material 28 is often in contact with the tissue immediately surrounding the stoma 18 and in some instances protrudes down into the stoma 18 as can be seen in FIG. 2. In such cases, this added material 28 can irritate and inflame the tissue surrounding the stoma thereby creating additional discomfort and problems for the patient.
There is therefore a need for an improved enteral feeding device design which helps reduce the potential for stoma irritation and trauma.